The present invention relates to an autofocusing system in the macro zone of a zoom lens.
Power zoom lenses driven by drive means such as a motor have recently been employed in so-called compact cameras fitted with an uninterchangeable photographic lens.
In an autofocusing system for such a compact camera equipped with the power lens, a zoom lens group is adjusted, in the zooming zone of a photographic zoom lens, in such a manner that an image of an object is formed on a film plane. Consequently, only a focusing lens group is driven to be in focus after the drive means is used to move and set the zooming lens group to have the certain focal length.
Incidentally, some photographic zoom lenses are designed to have the macro zone for use in close-up photographing by locating the zooming lens group outside the zooming zone.
In the macro zone, however, the focal length of the zooming lens group is constant and, because of photography is performed at a close distance, the distance between the photographic lens and the film needs adjusting so that the distance between the lens and the film corresponds to the distance between the lens and the object by delivering each lens group by a large amount to form an image of the object on the film.
Notwithstanding, a known arrangement is to control the zooming lens group in the macro zone independently of the autofocusing system, as in the zooming zone, such that the photographic lens can be brought into an in-focus condition by driving only the focusing lens group.
For the reasons set forth above, the photographic lens may not be brought into in-focus condition only by driving the focusing lens group, depending on the location of the zooming lens group on the optical axis.